1. Technical Field
The present invention relates to an ink-jet printer and, more particularly, to an ink-jet printer having an ink cartridge supporting a printhead integrally formed with a carriage assembly.
2. Related Art
Ink-jet printers are generally popular because they offer high printing speed, low noise, easy color printing, simply construction and low price. The concepts and operational principles of ink jet printers are well described, for example, in U.S. Pat. No. 4,475,116 for Ink Printer Equipped With An Ink Printing Head And Intermediate Ink Container Disposed On A Movable Carriage issued to Sicking et al., U.S. Pat. No. 4,755,836 for Printhead Cartridge And Carriage Assembly issued to Ta et al., U.S. Pat. No. 4,942,408 for Bubble Ink Jet Print Head And Cartridge Construction And Fabrication Method issued to Braun, U.S. Pat. No. 4,907,018 for Printhead-Carriage Alignment And Electrical Interconnect Lock-in Mechanism issued to Pinkerpell et al., U.S. Pat. No. 5,138,342 for Ink Jet Cartridge And Ink Jet Recording Apparatus Employing The Same issued to Kurata et al., U.S. Pat. No. 5,212,502 for Ink Jet Print Head Mounting Mechanism issued to Bowling, U.S. Pat. No. 5,216,448 for Ink Jet Recording Head Carriage And An Apparatus With Same issued to Unosawa et al., U.S. Pat. No. 5,404,158 for Ink Jet Printer Maintenance System issued to Carlotta et al., U.S. Pat. No. 5,448,274 for Ink Jet Recording Apparatus And Carriage Mechanism Therefor issued to Hirabayashi et al., U.S. Pat. No. 5,539,436 for Modular Carriage Assembly For An Inkjet Printer issued to Wilson et al., and U.S. Pat. No. 5,629,725 for Carriage Mount For An Ink Jet Cartridge issued to Buican.
In general, an ink jet cartridge is detachably mounted on a carriage assembly which supports a printhead, and traverses the printhead across the width of a recording medium in a line recording operation along a guide shaft for printing an image or character on the recording medium. An ink jet cartridge is typically constructed in and unitary, detachable cartridge which includes a printhead comprising a plurality of nozzles in the form of a nozzle plate mounted on one end, and an ink container containing a reservoir of ink, drop generating structures and electrically connections adapted for electrically coupling the printhead to the ink jet printer which provides drop generating energy in response to information signals generated by the ink jet printer. The principle behind this type of ink jet printer is the generation of a thermal pressure wave in the ink container and subsequent emission of ink droplets from the ink container through a plurality of nozzles arranged vertically at a front end of the printhead provided with the ink jet cartridge. The thermal pressure wave is generated by selected heating elements installed in the nozzles, which heat the ink contained within the nozzles until the ink is ejected through an ejection orifice of the nozzles to produce a flying droplet of the ink. The droplet is deposited on the recording medium so that a desired character and image can be formed.
When ink in the ink container is used up, however, the entire ink jet cartridge including the printhead needs to be replaced. This is required because the ink jet cartridge is typically constructed in a unitary structure regardless of whether such an ink jet cartridge involves a relatively large difference between the period in which the ink in the ink container is used up and the service life of the printhead. Although there are recent proposed constructions of an ink jet cartridge in which the ink container is detachably mounted to a printhead so as to permit replacement of the ink container and the printhead separately at different times as disclosed, for example, in U.S. Pat. No. 5,500,664 for Ink Jet Recording Apparatus And Detachably Mountable Ink Jet Cartridge issued to Suzuki et al., and U.S. Pat. No. 5,671,000 for Ink Jet Cartridge With Separable Ink Tank And Recording Head issued to Hirabyashi et al., the ink jet cartridge still needs to be taken out of the ink jet printer for replacement of the entire ink jet cartridge or an individual part of the ink jet cartridge.
A contemporary ink jet cartridge that is detachably mounted on carriage assembly as I have generally described, however, has several drawbacks. For example, the indirect connection of the computer interface with the printhead, i.e., between primary and secondary printing control cables, may result in a poor or unreliable connection and tends to cause malfunction. Such a computer connection also requires additional components and assembly time, which increases production cost. In addition, since the ink jet cartridge is a disposable item which includes printhead nozzles and secondary printing control cables, the entire cartridge must be discarded when ink supply is depleted, regardless of the condition of the nozzles or the associated cables and contacts, all of which tend to have long lifetimes when compared to the ink supply. This is both wasteful and cost-prohibitive.